Probably going to end up sperging out, but I wanted to sell my idea.
My map idea is a Gloomy/Forlorn War Torn City, ideally designed as a shoutout to the C&C Tiberian Sun Universe. However, I want the selling point to be Randomly Generated and Evolving Environmental Hazards.
The official map setting/explanation can be a city where Horzine had a lab experimenting with alternative energy using crystals, and things went wrong.The area is now a living minefield with volatile crystals growing in every nook and cranny of the city.
Gameplay wise, the crystals would randomly spawn at choke/holdout points around the map, like ammo crates. It rewards careful kiting and moving around the map, but doesn't punish for camping. The purpose of the crystals would be to give players in a pinch an extra edge/fighting chance. About as helpful as that extra nade or magazine you didn't have, but more reliable than that ammo crate you couldn't find but needed.
In regards to the crystals changing over time. Imagine that the crystals are initially green, shooting or hitting them at that stage would cause them to shatter and emit radiation. The effect would be similar to crawler gas, slightly damaging player and zed alike, obscuring vision, BUT also instantly panic all zeds, even raging ones (like nuke).
Leave them alone for awhile, they grow into blue crystals. Shattering these has a 50/50 chance of either EMPing (derage big zeds temporarily or panic) or freezing zeds. Lower chance for self inflicted harm and generally more helpful crowd control wise.
Leave the blue crystals alone long enough, they grow into their final stage, red crystals with the damage of 1 or 2 TNTs plus knockdown or stun. Higher risk of killing yourself, higher reward of quickly dealing with a group of big zeds that are causing a wipe.
The basic idea is to create environmental hazards that act as a mix and match of different perk grenades. Helpful but not too OP.